What This Backshell Does in the Harness
The TE Connectivity Deutsch HD18-003 is a plastic backshell designed for the HD10 series of circular connectors. It provides cable strain relief and termination point protection at the rear of the connector, with a 180° straight cable exit that keeps the cable bundle aligned with the connector axis. The shell size 3 fits the corresponding HD10 connector bodies, and the integrated tie wrap holder secures the cable without requiring a separate clamp. The cable opening measures 1.138" (28.91 mm), which accommodates a substantial cable bundle — think multi-conductor power or signal cables typical in heavy-duty truck, off-road vehicle, and industrial equipment harnesses. The gray plastic housing is unshielded, so this backshell is suited for applications where EMI shielding is handled at the connector or cable level, not at the backshell.